The present invention relates to a copier having an automatic document feeder (ADF) and operable in a two-sided copy mode.
A copier with an ADF is often constructed to be selectively operable in a one-sided copy mode for reproducing a document image on only one side of a paper sheet and a two-sided copy mode for reproducing document images on both sides of a paper sheet. This type of copier usually incorporates a reversing device for reversing a paper sheet undergone a copying procedure. Assume that such a copier is used to reproduce a combined stack of one-sided and two-sided documents on paper sheets. Then, it is a common practice to divide the documents into one-sided documents and two-sided documents beforehand, reproduce the one-sided documents in a one-sided copy mode and the two-sided documents in a two-sided copy mode independently, and then rearrange the documents in order of page. Such an operation is time- and labor-consuming. Especially, when the desired documents are not numbered, it is necessary for the operator to memorize the order of all the documents as to page beforehand. When a great number of documents are to be reproduced, a substantial period of time has to be consumed in sorting the documents into one-sided and two-sided documents. Should all such documents be continuously copied in the two-sided mode in order to save time and labor, the copying operation would be effected even with the blank sides of one-sided documents to increase the copying time.